Exhaust gas pipes with an encapsulation cause a minimal heat loss from the exhaust gas and are used preferably where the energy of the exhaust gas is to be converted into work in a down-stream turbo-charger or when the surface temperature of the exhaust gas pipe shall be kept low.
German Patent Publication (DE-PS) 3,635,478 discloses an encapsulated exhaust gas pipe for a turbo-charged internal combustion engine. An inner duct for the exhaust gases is arranged in a gas-tight housing. The inner duct is assembled from individual sections, whereby the length of one section corresponds approximately to the spacing between cylinders of the internal combustion engine. The sections consist each of two groove-type channels with flanges. The flanges are connected to the housing by screws. Cover strips apply a force to the groove-type channels to damp vibrations of the groove-type channels.
The production of the inner sections of two parts leads to increased costs in keeping these parts in stock and in mounting these parts. The mounting of the exhaust gas pipe with cover strips requires a careful adaptation and is thus cost intensive.